Aerodynamic control surface movement monitoring system

Abstract

An actuator system for controlling a flight surface of an aircraft includes a first actuator having a first actuator input and a first linear translation element that moves based on rotational motion received at the first actuator input and a first sensor coupled to the first linear translation element that generates a first output based on a displacement of the first linear translation element. The system also includes a second actuator having a second actuator input and a second linear translation element that moves based on rotational motion received at the second actuator input and a second sensor coupled to the second linear translation element that generates a second output based on a displacement of the second linear translation element. The system also includes a control unit that receives the first and second outputs and determines if an error condition exists for the system based on first and second output.

The invention claimed is: 
     
       1. An actuator system for controlling a flight surface of an aircraft, the system comprising:
 a first actuator having a first actuator input and a first linear translation element that moves linearly based on rotational motion received at the first actuator input; 
 a first sensor that includes a first rotational input coupled to the first linear translation element that measures linear motion of the first linear translation element based on rotation of the first linear translation element as it moves linearly and that generates a first output based on the linear motion of the first linear translation element; 
 a second actuator having a second actuator input and a second linear translation element that moves linearly based on rotational motion received at the second actuator input; 
 a second sensor that includes a second rotational input coupled to the second linear translation element that measures linear motion of the second linear translation element based on rotation of the second linear translation element as it moves linearly and that generates a second output based on the linear motion of the second linear translation element; and 
 a control unit that receives the first and second outputs and determines if an error condition exists for the system based on first and second output. 
 
     
     
       2. The actuator system of  claim 1 , wherein the flight surface is a flap. 
     
     
       3. The actuator system of  claim 2 , wherein the error condition is a flap skew condition and is determined when the signals from the first and second sensors do not match. 
     
     
       4. The actuator system of  claim 1 , further comprising:
 a drive shaft coupled to the first input and the second input; and 
 a drive unit that causes the drive shaft to rotate based on signals received from the control unit. 
 
     
     
       5. The actuator system of  claim 4 , wherein the error is an actuator malfunction and is determined when a drive shaft's rotation is not proportional to one of the first or second outputs. 
     
     
       6. The actuator system of  claim 1 , wherein the first sensor is one of:
 a rotatory variable transformer, a liner variable transformer, a synchro/resolver or an encoder. 
 
     
     
       7. The actuator system of  claim 1 , wherein the first linear translation element is a ball screw. 
     
     
       8. The actuator system of  claim 1 , wherein the first linear translation element is a hydraulic actuator. 
     
     
       9. A method of controlling and monitoring an aircraft control surface, the method comprising:
 sending a control signal from a control unit to a drive to cause a drive shaft to rotate; 
 generating a first output with a first sensor that includes a first rotational input coupled to a first linear translation element of a first actuator, the first sensor measuring linear motion of the first linear translation element based on rotation of the first linear translation element as it moves linearly and indicating an amount of linear motion of the first linear translation element; 
 generating a second output with a second sensor coupled to a second linear translation element of a second actuator, the second sensor measuring linear motion of the second linear translation element based on rotation of the second linear translation element as it moves linearly and indicating an amount of linear motion of the second linear translation element; 
 comparing an expected sensor outputs to the first and second outputs with the control to determine if an error condition exists; and 
 generating an error indication when the error condition exists. 
 
     
     
       10. The method of  claim 9 , wherein the flight surface is a flap. 
     
     
       11. The method of  claim 9 , wherein the error condition is a flap skew condition and is determined when the signals from the first and second sensors do not match. 
     
     
       12. The actuator system of  claim 9 , wherein the error is an actuator malfunction and is determined when a drive shaft rotations is not proportion to one of the first or second outputs. 
     
     
       13. The method of  claim 9 , wherein the first sensor is one of: a rotatory variable transformer, a liner variable transformer, a synchro/resolver or an encoder. 
     
     
       14. The method of  claim 9 , wherein the first linear translation element is a ball screw. 
     
     
       15. The method of  claim 9 , wherein the first linear translation element is a hydraulic actuator.